Share of foreigners in Europe

According to this infographic made by Statista  the highest percentage of foreign population lives in Luxembourg. 

The highest number of foreigners living in any European state can be found in Germany (7.4 million people), but if we compare the total number of natives with the percentage of foreigners in all European countries, Luxembourg is actually the EU member with the highest share of non-nationals (44.5%), followed by Cyprus (19.6%) and Latvia (15.6%).

At the end of this list there are Germany, Greece and the UK.

How could you explain that Luxembourg, Cyprus and Latvia are at the top of this list?